Checkerwork construction



July 22, 1930. C, w, ANDREWS ET AL 1,771,292

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cHEcKERwoRK CONSTRUCTION Filed July 13, 1929 c. w. ANDREWS E1' AL1,771,282

cHEcKERwoRx CONSTRUCTION Filed July 15, 19.29 zshee-.s-sheet 2 July z2,1930;

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Patented ...lul 2, litt@ CHARLES W. MDAREWS, JGHN PHILLIP GRILLJE, HARRYL. WETHERBEE, AND ARLES E. DOUGAN, 0F CHICAGO, ILLINQIS, .ASSIG'NGRS TOH. BRASSERT & COMPANY, 0F HICAGQ, JLLINOIS, A CURPORATION 0F ILLINOISCHEOKERWORK CONSTRUCTION Application filed. July 13,

This invention relates to a new and improved construction of checkerworkfor regenerative purposes, and more particularly to a design especiallyadapted for use in hot blast stoves.

rllhe invention relates to a design adapted to substantially increasethe heat transfer efficiency in checkers and to increase the heatingsurface in a stove of given size.

rThis invention is in the nature of a modiication or improvement of thatdisclosed 1n the prior a plication of Brassert, Hulse and Andrews, erialNo. 247,570, led January i8, 1928.

Het blast stoves for heating the air for blast furnaces have beenconstructed wlth checkerwork of various design. The usual checkeremployed in this country is built up out of brick placed on edge in sucha way as to form square openings. hexagonal brick with roundfholes werefrequently used. Other special shapeshave been employed in the past,generally with a View of stifening the checker column and preventingshifting of the checkers through pressure from the expanding combustionchamberwall, but in every case the checker openings were of the samesize from top to bottom and the heating surface was the same in everycross section of the checkerwork throughout the height of the stove,which is usually from 'eighty to one hundred and ten feet.

This uniform construction has the disadvantage that the top checkers domost of the Work of heat exchange, both during the period of heating andof giving off heat to the blast. The top checkers are heated to verynearly the same temperature as the combustion chamber, that `is, to abright red heat, and the checkers about thirty feet down are heated to adull red heat. Below this point the checkersremain black and the lowerhalf of the checker column does but very little work. In other Words,the temperature at the top of the checkers is usually around 20000 F.,thirty feet down approximately l200 and fifty feet down about 8000, orvery closeto the usual chimney temperature of 600.

rllhere are two reasons for the inefficient ln' former years 1929.Serial No. 377,975.

checkerwork. One reason is thatv the heat exchange is more rapid andmore penetrating the higher the difference in temperature of the heatexchanging mediums, In other Words, the heat transfer is a function ofthe heat head, but it is also a function of the velocity of the gases.'When the stove checkers are of equal design all the way through .thechecker column, the combined open area through the checkers being thesame from top to bottom, the velocity of the hot gases is very muchgreater at the top of the check-` ers than at the bottom, also thevelocity of the cold blast is very much greater at the top of thecheckers than at the bottom. lf the temperature at the top of thecheckers is 2000o and at the bottom 500, the ratio of velocities isapproximately two and one-half to one. In the case of the cold blast,the diner-ence is even greater, being more nearly three to one when highblast temperatures are carried.

We have vdeveloped a type of checkerwork -which permits of a decrease inthe effective passage area for gases in the bottom part of the stove ascompared to the top part of the stove, with the result that thevelocities may be equalized to whatever extent desired, and a materialincrease of heating surface ob tained. lt will be possible to change theeffective area through a plurality of steps in the height of the stove.This decrease in effective passage area is caused by the insertion offiller brick in the passages between the main brick and the passagesextending through the main checkerbrick. These filler brick, in additionto decreasing the passage area, accomplish a very material increase inthe heating surface of the checkers. Filler brick of larger sizes areused in the lower sections to decrease the passage area, and fillerbrick of progressively smaller` area are used in the intermediate andupper sections so that the effective passage area is modified. lt willbe understood that any desired number of sizes of filler brick may beused, but for purposes of illustration We have shown three such fillerbrick. The top portion of the stove is preferably formed with no fillerbrick located in the passages so that at this point the entire passagearea is available.

Ve have provided octagonal brick having a substantially square interiorpassageway, the brick being so proportioned that when placed together ina horizontal course the passageways formed between the brick are sub.stantially identical in size and contour, with the passages extendingthrough the brick. The octagonal brick are formed with-alternate sidesof greater and lesser horizontal eX- tent. The sides of greater extentare opposite the sides of the interior passageway and serve to formsides of the pasageways between adjacent brick. The sides of lesserhorizontal extent are located outside the corners of the interiorpassageway and are placed in contact with those of adjacent brick whenthe checkwork is built up. By this form of construction a maximumcontact surface is provided and a construction is formed in which thethickness of the walls between the various passageways is maintainedsubstantially con-` stant.

One of the difficulties attendant to the use Aof stoves of thischaracter has been the fact that when vertical passageways are obstruct-Id by the deposit of foreign matter or by spalling or breaking of brick,the entire vertical passage has been lost to the stove, as no means havebeen provided for dthe horizontal passage of gases from one verticalpassageway to another. In our preferred form of construction we providenotches in ends of certain of the brick, these notches formingpassageways so that if a vertical passageway is obstructed at one pointit will be possible for gases to use other portions of that passagewayby passing from and to adjacent passageways.

One of the difficulties with this form of construction has been the factthat due to the difference in size or contour between the passagesformed between the brick and those passing through the brick, it hasbeen impossible to break joint on the brick horizontally. It hasbeennecessary to have the brick formed in continuous columns throughoutthe height of the stove. Our form of construction which providespassageways of substantially equal shape and area through and betweenbricks,

permits us to break joint in successive courses and thus thoroughly bondthel structure. Ve also provide means whereby the filler brick may bestarted at a different level than the main brick so that there is abreak of the vertical joints as between filler and main bricks whichserves t0 further bond the structure iii this direction.

It is an object of the present invention to provide a new and improvedconstruction and design of checkbrick and checkerwork.

It is a further object to provide a construction in which thepassageways through and between brick may be similar in size andcontour.

It is an additional object to provide means for graduating the effectivepassage area for gases in the different sections of the stove.I and forproviding additional heating surface.

It is an additional object to provide checker 'construction which may bebonded by breaking joint both horizontally and vertically.

It is also an object to'provide a checkerbrick and construction thereofwhich will be simple in design and adapted for commercial manufactureand installation.

Other and further objects will appear as the description proceeds.

We hare shown certain preferred embodiments of our invention in theaccompanying drawings, iiiwhich- Figure 1 is a plan View of the upperportion of a. stove taken on line 1-1 of Figure 6;

Figure 2 is a plan View of an intermediate portion of the stove taken online 2-2 of i Figure 6;

Figure 3 is a plan View of a lower intermediate portion taken on line 33 of Figure 6;

Figure 4 is a plan view of a lower portion of a stove taken on line 4--4of Figurel 6;

Figure 5 is a plan view of a portion of the supporting structure takenon line 5 5 of Figure 6;

Figure 6 is a diagrammatic fragmentary elevation showing the relation ofthe various form of brick;

Figure 7 is a fragmentary section taken on line 7-7 of Figure 1; and

Figure 8 is a perspective view of one of the lower supporting members.

Referring first to Figures 1 and 7,the octagonal brick l1 is providedwith the wider faces 12 and the narrower faces 13, the narrower faces 13of adjacent brick contacting with each other. The vertical passageways.14 are formed extending between adjacent brick and also extendingthrough the individual brick. While the passages between brick havesquare corners, it will be noted that the corners of the passagesthrough the brick have a rounded fillet 15 which is desirable in orderto strengthen the brick and prevent their cracking at the corners. Thisfillet, however, is small and the passages through and between the brickare substantially equal in contour and effective passage area for gases.As shown in Figure 1, the brick 11 shown in full lines are placed so asto break joints with the brick of the lower courses. This is indicatedby the broken lines 16 which show the meeting faces of the lower brickand bv the curved lines 17 which indicate the corner fillets on thebrick of the lower course which are located below the passageways formedbetween the brick of the upper course.

As best shown in Figure 7 the brick 11 are provided with the roundednotches 18 formed on their edges on the wider faces 12,

which form sides of the intermediate passageways. These notches 18 arevshown as mating on adjacent brick thus forming circular passagewaysextending transversely between adjacent vertical passages. rEhisprovides intercommunication throughout the checkerwork. 1t will beunderstood that these transverse passages may be provided on some or allof the brick and may or may not consist of mating notches, as desired.For example, the notches may be only in one end of a brick.

'Ehe next lower section of the checkerwork, as shown in Figure 2,consists of the main brick 11 with additional filler brick 19 placeddiagonally of the passageways extending both through and between themain brick 11. These liller brick 19 may have rounded ends 20 so thatthey conform to the :fillets 15 of the interior passageways or fit witha slight clearance in the passageways formed between adjacent brick 11.As shown in Figure 2, the brick 19 may be placed at right angles to eachother in successive courses. 1f desired, a number of courses of brick.19 may be placed in one direction with a following number of brick 19placed in the cross direction. 'llhese filler brick providesubstantially triangular passageways 21 Jfor the passage ot gases.

Figure 3, which shows a lower section of the checkerwork, shows the samemain brick 11 and a diierent type of filler brick 22 placed in thepassageways. rllhis lbrick 22 is similar in general contour to the brick19 but is provided with the laterally rounded extensions 23 which extendat right angles to the main body of the brick and which, when the brickare placed at right angles to each other in successive courses, as shownin Figure 3, will cause the portions 23 of one brick to overlie the mainbody portion of the brick below. 1t will be noted that these brick alsoform the triangular passageways 211er passage ot gases, thesepassageways being in direct extension of the passageways 21 shown inFigure 2.

The lower construction shown in Figure 4 includes the same main brick 11and a filler brick 24 which is in the shape of a cross having arms 25extending to all four corners of the substantially square passageways.This brick, since it is symmetrical about both axes, can only be lacedin the passageways in one position. hese brick, however, continue toleave the triangular passages 21 free for passage of gases.

The lower supporting structure is shown in Figure 5 and in the lowerportion of Figure 6, together with the filler supporting member 26 whichis shown in perspective view in Figure 8. The checkerwork is supportedas in the usual construction on arches 27 shown in Figure 6. A layer ofrectangular brick 28 is placed across the arches 27 and this layer ofbrick 28 su ports a second layer of brick 29, some of w ich extendintermediate the arches 27.

1t is desirable to have the filler brick 19, 22 and 24 break jointvertically with the main brick 11 and to give this result the lillerbrick supporting members 426 are provided, these being preferably formedof metal such as cast iron, and being shown in plan view 'in Figure 5where they are supported on the upper transverse rectangular brick 29.These supporting members 26 have the meeting surfaces 30 where they fittogether to form a laterally supported structure and have the transverseseats 31 to support the filler brick. These seats 31 are located at halfthe height of the members 26. Special brick 32 are provided havingchamfered ends 33 to fit together intermediate the supportin member 26,as best shown in Figure 5. Tbese brick 32 are also supported on theupper rectangular brick layer 29. The brick 32 are of the full height ofthe members 26 which corresponds to the full height of the main checkerbrick 11. Consequently, when the main brick are placed upon the lowersupporting construction shown in Figure 5, these main brick will each besupported upon four of the brick 32 and will also be supported upon theuppermost portions of certain of the members 26. r1`he seat 31 will belocated below the bottom of the first layer of brick 11 a distance equalto half the height of such brick, so that the filler brick resting onthe seat 31 will extend only half way up int-o the first layer of brick11. By continuing this structure u ward it will be understood that theller rick and main brick will break joint vertically throughout theheight of the regenerator structure.

By placing the main brick, as shown in Figures 1 to 4, to break jointhorizontally, a strong and rigid structure is provided which isinterlocked both vertically and horizontall Preferably we provide thehorizontal openings connecting the vertical assageways in each one ofthe octagonal brick in the uppermost layer of each intermediate section.For instance in the uppermost section, which usually has no fil erbrick, we do not need to provide horizontal cross connections. In theuppermost layer of brick of the second section, however, containing thenarrowest filler brick, we preferably provide horizontal cross ducts orconnections in each of the octagonal brick which are preferably at fourpoints in each brick, as shown in the accompanying drawings. At thispoint the variation in gas and air velocities from the average which weare striving to maintain, is at its maximum, that is, the velocity offiow in each section is greatest within the top layer. Therefore, it isevitlf) llUU

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dently more important to allow the gases to redistribute themselves atthis point, in case of the plu ging up of one or the other of thevertical ues. Also it is at this point that such plugging up is mostlikely to occur, on account of the change at this point from a larger toa smaller flue section by the insertion of the filler brick.

The same idea may be followed in'the lowersections of the checkercolumn, the cross flues being applied to the top layer of brick in eachsection. 1n a balanced draft stove, for instance, of the centercombustion Diehl type, more of these cross connections can be appliedthan in the ordinary side combustion stove, without causing a diagonalflow of the gases toward the flues nearer the exit.

While we have shown certain preferred forms of construction it will beunderstood that the main and Ifiller brick may be modified somewhat inform and construction, and

the supporting members for the filler brick may alsobe modified and theseat may be located at other portions than half way up the supportingmember if it is desired to break the joints at other points. The formsshown are to be understood as illustrative only and we contemplate suchchanges and modifications as come within the spirit and scope of theappended claims.

We claim n 1.A 'checkerwork construction comprising a plurality ofsuperposed layers of brick,

4"the brick having passages formed therethrough and being placed so asto form passages therebetween, the brick in superposed layers being soplaced that the passages through the brick in one layer are inregistration with the` passages between brick in another layer, andcontinuous columns of filler brick placed in said passages to reduce theeffective area and increase the heating surface thereof.

Q. A checkerwork construction comprising a plurality of superposedlayers of brick, the brick having passages formed therethrough and beingplaced so as to form passages therebetween, the brick in superposedlayers being so placed that the passages through the brick in one layerare 1n registration with the passages between brick in another layer,and continuous columns of filler brick placed in said assages to reducethe effective area thereof?- the filler brick breaking joint verticallywith the checkerbrick.

3. A checkerwork construction comprising a plurality of superposedlayers ofbrick, the brick having passages formed therethrough and beingplaced so as to form passages therebetween, the brick in superposedlayers being so placed that the passages through thebrick in one layerare in registration with the passages between brick in another layer,and continuous columns of filler brick placed in said passages to reducethe effective area thereof, the filler brick in all passages in anyhorizontal plane being similar in size and contour whether in or betweenbricks.

4. A checkerwork construction comprising a plurality of superposedlayers of brick, the brick having passages formed therethrough and beingplaced so as to form passages therebetween, the brick in superposedlayers being so placed that the passages through the brick in one layerare in registration with the passages between brick in another layer,and filler brick placed in said passages to reduce the effective areathereof, the filler brick differing in size at different points in theheight of the checkerwork.

5. A checkerwork construction comprising a plurality of superposedlayers of brick, the brick having passages formed therethrough and beingplaced so as to form passages therebetween, the brick in superposedlayers being so placed that the passages through the brick in one layerare in registration with the passages between brick in another layer,and filler brick placed in said passages to reduce the effective areathereof, the filler brick differing in size at different points in theheight of the checkerwork and being largest at the bottom portionthereof.`

6. A checkerwork construction comprising a plurality of superposedlayers of brick, the brick having passages formed therethrough and beingplaced so as to form passages therebetween, the brick in superposedlayers being so placed that the passages through the brick in one layerare in registration with the passages between brick in another layer`and continuous columns of filler brick placed in said passages to reducethe effective area thereof, certain of the filler brick being placed atan angle to other filler brick in the same passage.

7. A checkerwork construction comprising a plurality of superposedlayers of brick, the brick having passages formed therethrough and beingplaced so as to form passages therebetween, the brick in superposed-layers being so placed that the passages through the brick in one layerare in registration with the passages between brick in another layer,and filler brick placed in said passages to locate upper filler brickwithin the vertical projection of lower filler brick and reduce theeffective area thereof, the filler brick being so designed and placed asto leave continuous unobstructed passages throughout the height of thecheckerwork.

8. A checkerwork construction comprising a plurality of superposedlayers of brick, the brick having passages formed therethrough and beingplaced so as to form passages therebetween, the brick in superposedlayers being so placed that the passages through the brick in one layerare in registration with the passages between brick in another layer,filler brick placed in said passages to reduce the effective areathereof, the filler brick breaking joint vertically with thecheckerbrick, and means at the bottom of the checkerwork to support thelower Eller ricll; at a lower level than the lower checkerric Signed atChicago, Illinois, this 12 day of July, 1929.

CHARLES W. ANDREWS. JOHN P. GRILLI. HARRY L. WETHERBEE. CHARLES. E.DOUGAN.

